Is it possible to create CSS style sheets outside of Kentico with either SASS or LESS?

I'm building my first Kentico 8.2 project from scratch and I am wondering whether or not it is possible to edit the style sheet externally from the CMS? For example, I would like to edit in Sublime text using either SASS or LESS. Does anyone know if this is possible, and where exactly is the style sheet stored in the directory. I've been looking for it but to no avail.